ACL\_EXTENDED\_FILE(3) Library Functions Manual ACL\_EXTENDED\_FILE(3) # [NAME](#NAME) `acl_extended_file`, `acl_extended_file_at`, `acl_extended_file_nofollow` — test for information in ACLs by file name # [LIBRARY](#LIBRARY) Linux Access Control Lists library (libacl, -lacl). # [SYNOPSIS](#SYNOPSIS) `#include ` `#include ` `int` `acl_extended_file`(`const char *path_p`); `int` `acl_extended_file_at`(`int dirfd`, `const char *path_p`, `int at_flags`); `int` `acl_extended_file_nofollow`(`const char *path_p`); # [DESCRIPTION](#DESCRIPTION) The [`acl_extended_file`](#acl_extended_file)() function returns `1` if the file or directory whose pathname is given in `path_p` is associated with an extended access ACL, or if the directory referred to by `path_p` is associated with a default ACL. The function returns `0` if the file has neither an extended access ACL nor a default ACL. If `path_p` is a symbolic link, `acl_extended_file`() returns information about the file or directory the link refers to. An extended ACL is an ACL that contains entries other than the three required entries of tag types ACL\_USER\_OBJ, ACL\_GROUP\_OBJ and ACL\_OTHER. If the result of the [`acl_extended_file`](#acl_extended_file~2)() function for a file object is `0`, then ACLs define no discretionary access rights other than those already defined by the traditional file permission bits. Access to the file object may be further restricted by other mechanisms, such as Mandatory Access Control schemes. The [access(2)](/man/os/acl/access.2) system call can be used to check whether a given type of access to a file object would be granted. ## [`acl_extended_file_at`](#acl_extended_file_at)() The `acl_extended_file_at`() function operates in exactly the same way as `acl_extended_file`(), except for the differences described here. If the pathname given in `path_p` is relative, then it is interpreted relative to the directory referred to by the file descriptor `dirfd` (rather than relative to the current working directory of the calling process, as is done by [`acl_extended_file`](#acl_extended_file~3)()). If `path_p` is relative and `dirfd` is the special value `AT_FDCWD`, then `path_p` is interpreted relative to the current working directory of the calling process (like [`acl_extended_file`](#acl_extended_file~4)()). If `path_p` is absolute, then `dirfd` is ignored. The `at_flags` argument can either be 0, or include one or more of the following flags ORed: [`AT_EMPTY_PATH`](#AT_EMPTY_PATH) If `path_p` is an empty string, operate on the file referred to by `dirfd` (which may have been obtained using the [open(2)](/man/os/acl/open.2) `O_PATH` flag). In this case, `dirfd` can refer to any type of file, not just a directory. [`AT_SYMLINK_NOFOLLOW`](#AT_SYMLINK_NOFOLLOW) If `path_p` refers to a symbolic link, do not dereference it: instead, fail the operation and set the global variable `errno` to `ENOTSUP`. This indicates that the symbolic link cannot have ACLs. ## [`acl_extended_nofollow`](#acl_extended_nofollow)() The `acl_extended_file_at`() function operates in exactly the same way as `acl_extended_file`() with a `dirfd` value of `AT_FDCWD` and an `at_flags` value of `AT_SYMLINK_NOFOLLOW`. # [RETURN VALUE](#RETURN_VALUE) If successful, these functions return `1` if the file object referred to by `path_p` has an extended access ACL or a default ACL, and `0` if the file object referred to by `path_p` has neither an extended access ACL nor a default ACL. Otherwise, the value `-1` is returned and the global variable `errno` is set to indicate the error. # [ERRORS](#ERRORS) If any of the following conditions occur, these functions return `-1` and set `errno` to the corresponding value: \[[`EACCES`](#EACCES)] Search permission is denied for a component of the path prefix. \[[`EBADF`](#EBADF)] The argument `path_p` is relative but the argument `dirfd` is neither `AT_FDCWD` nor a valid file descriptor. \[[`EINVAL`](#EINVAL)] An invalid flag was specified in the `at_flags` argument. \[[`ENAMETOOLONG`](#ENAMETOOLONG)] The length of the argument `path_p` is too long. \[[`ENOENT`](#ENOENT)] The named object does not exist or the argument `path_p` points to an empty string. \[[`ENOTDIR`](#ENOTDIR)] A component of the path prefix is not a directory. The argument `path_p` is relative and the argument `dirfd` is a file descriptor referring to a file other than a directory. \[[`ENOTSUP`](#ENOTSUP)] The argument `at_flags` includes the flag `AT_SYMLINK_NOFOLLOW` and `path_p` is a symbolic link. The file system on which the file identified by `path_p` is located does not support ACLs, or ACLs are disabled. # [STANDARDS](#STANDARDS) This is a non-portable, Linux specific extension to the ACL manipulation functions defined in IEEE Std 1003.1e draft 17 (“POSIX.1e”, abandoned). # [SEE ALSO](#SEE_ALSO) [access(2)](/man/os/acl/access.2), [acl\_get\_file(3)](/man/os/acl/acl_get_file.3), [acl(5)](/man/os/acl/acl.5) # [AUTHOR](#AUTHOR) Written by Andreas Gruenbacher ⟨andreas.gruenbacher@gmail.com⟩. June 5, 2026 Linux ACL --- Document: acl_extended_file_nofollow(3) from acl 2.4.0-r4 (Chainguard OS) Source: https://git.savannah.nongnu.org/git/acl.git